Tumor Necrosis Factors (TNF's) are protein-containing molecules which are excreted by macrophage cells in several species, including man, mouse and rabbit, in response to endotoxin or other appropriate stimuli. TNF's have been shown to be capable of killing cells of several different established animal and human cancer cell lines and of producing ablation of tumors in tumor-bearing animals through production of an hemorrhagic necrosis. Recently, human recombinant TNF, designated Hr-TNF, has been produced and is currently undergoing clinical testing for its effective and safe treatment of human cancers. This invention relates to a further improvement in the efficacy of TNF's (including Hr-TNF) in treatment of cancerous tumors in animals or man through additional administration of a C-Reactive Protein (CRP).
Human CRP (for review see Gewurtz H. et al., Advances in Internal Med. 27, 345-372, 1982) was first detected as a precipitin of bacterial polysaccharides in sera of patients with inflammatory diseases. Human CRP specified by a gene localized on chromosome I (Whitehead, A. S. et al., Science 221, 69-71, 1983) and consists of a single polypeptide chain containing 187 amino acids (Oliveria, E.B. et al., J. Biol. Chem. 254,
489-502, 1979) which is highly homologous to CRP's as isolated from various species including plaice, rabbit and chicken (Pepys, M. B. et al., Nature 273, 169-170, 1978). Recent studies based on the deoxynucleotide sequencing of the cDNA clones and of the genome specifying human CRP suggest that the human CRP is a larger protein than described in the Oliveria reference in that it contains a segment of 19 aminoacids not detected in the Oliveria study that employed aminoacid sequencing (Lei, K. J. et al., J. Biol. Chem. 260, 13377-13383, 1985: Woo P. et al, J. Biol. Chem. 260, 13384-13388, 1985). Chemically the various CRP's are pentraxins and are readily characterized by formation of pentameric pentagonal structures as observed by electron microscopy (Osmond, A.P. et al., Proc. Natl. Acad. Science USA, 74, 739-743, 1977). Human CRP in the presence of calcium ion binds selectively to the phosphorylcholine moiety present in complex bacterial polysaccharides and in disturbed membranes of eukaryotic cells, and in the absence of calcium to polycations such as chromatin. Human CRP is present at less than 10 .mu.g/ml in normal human serum but can rise over 1,000 fold through production as an acute phase liver protein in response to trauma and inflammation (for review see Koj A "Acute Phase Reactants" in "Structure and Function of Plasma Proteins" Allison A., Ed., pp. 73-131, Plenum Press, New York, 1974). The physiological function of Human CRP is not fully defined. Human CRP has been shown to selectively bind at the site of trauma. Human CRP-C polysaccharide complexes have been shown to bind complement and to activate the classical complement cascade (Kaplan, M. H. and Volanakis, J. E., J. Immunol. 112, 2135-2147, 1974). CRP has also been shown to modulate the physiological activities of platelets, macrophages and NK cells.
Despite these varied physiological activities of human CRP its use in clinical medicine has been restricted to date to its observation as a diagnostic of trauma and inflammation, and particularly as an early diagnostic indicator of cardiac trauma. The use of human or other species CRP's in the therapeutic interventions was unknown except for a single report of protection of mice exposed to Streotococcus pneumoniae with human CRP (Mold, C. et al., J. Exp. Med. 154, 1703-1708, 1984) and a report on inhibition of lung metastases in mice bearing a fibrosarcoma and administered liposomes containing human CRP (Deodhar, S.D. et al., Cancer Res. 42, 5084-5088, 1982).